Arthropod borne viruses have developed a complex life cycle adapted to alternate between insect and vertebrate hosts. These arthropod-borne viruses belong mainly to the families Togaviridae, Flaviviridae, and Bunyaviridae. Flavivirus is a genus of the family Flaviviridae. This genus includes such viral infections as West Nile virus, dengue virus (DENV), Tick-borne Encephalitis virus, yellow fever virus, and zika virus (ZIKV) that may cause encephalitis. Alphavirus is a genus of the family Togaviridae. This genus includes such viral infections as chikungunya virus (CHIKV), Venezuelan Equine Encephalitis virus (VEEZ), and Eastern Equine Encephalitis virus.
Zika virus (ZIKV) is a single stranded RNA virus transmitted to humans primarily via Aedes aegypti mosquitos and other mosquitos of the Stegomyia subgenus. ZIKV can also be transmitted through sexual intercourse, a blood transfusion, or from a pregnant woman to her fetus. Infection during pregnancy can result in microcephaly and other severe fetal brain defects. Additional problems detected among fetuses and infants infected with ZIKV before birth include as defects of the eye, hearing deficits, and impaired growth. Increased reports of Guillain-Barre syndrome have also been observed in areas affected by Zika. Until recently, only sporadic human ZIKV infections had been reported. Since 2007, ZIKV has expanded from Asia and Africa to include both North and South America.
DENV is a mosquito-borne virus estimated to cause 50-100 million infections each year. DENV infections can result in serious diseases including dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, and may even result in death. This virus is considered by the World Health Organization to be the most important mosquito-borne viral disease worldwide.
Originally isolated in Tanzania, sporadic outbreaks of CHIKV have continued to plague Asia and Africa. In 2007, the first outbreak in Europe was documented with over 200 confirmed cases. To date, CHIKV has been identified in over 40 countries including the United States of America. The symptoms of CHIKV, which include fever, rash, and severe joint pain, are commonly indistinguishable from ZIKV and DENV. While most patients usually recover after days to weeks, some may develop chronic arthritis. Additionally, death related to Chikungunya infection has been reported in older patients or patients with weakened immune systems.
Currently, there are no approved treatments for ZIKV, DENV, or CHIKV. Despite the widespread distribution and severity of the effects of these viral infections, a treatment for ZIKV, DENV, and CHIKV has remained elusive. Thus, there remains a need for antiviral agents capable of targeting these viruses and methods of making and using same.